1. Field of the Invention
The present invention is a self contained, trailer mounted system with condenser for cooling and condensing those oil well gases that can be condensed and with a separator for separating the condensed portion from the non-condensable portion of the gas stream so that they can be recovered as liquid hydrocarbons. The system is powered by the gas pressure from the well and operates without any outside utilities so that it can be used at new well sites where infrastructure has not been built to support the well.
2. Description of the Related Art
In today's era of oil and gas well drilling, often wells will be drilled in remote locations where there are no utilities and no gas gathering pipelines. In shale areas such as the Baaken, Marcellus, Utica, and Eagle Ford areas, the wells are known to produce significant quantities of very light gravity crude oil, condensate (also known as natural gas liquids or NGLs) and natural gas in abundance. Since the completion technologies are relatively new, and these fields are quite large in geographical area, they lack the infrastructure necessary to bring all of the hydrocarbons into the commercial stream. At these wells, it has not been feasible to condense those hydrocarbons that exit the wellhead in gaseous state that might otherwise have been condensed to a liquid state and pumped to an oil tank. Therefore, large quantities of valuable hydrocarbon liquid rich natural gas are being released into the atmosphere, either directly or through venting or flaring. Often the condensable hydrocarbons are being burned with the non-condensable gases in flares at the wellhead, resulting in the loss of a large amount of recoverable hydrocarbons. With the high price of petroleum, this loss can add up to a considerable loss of revenue.
Also, the state and locate EPA offices in North Dakota, Pennsylvania, Ohio and Texas are now requiring that all wellhead gas be conditioned to remove as much of the valuable natural gas liquids as possible. This adds to the need for a new technology to remove the natural gas liquids prior to venting or flaring.
At the majority of these new wells, all gas and valuable natural gas liquids are being flared and completely destroyed by burning. The present system condenses and captures a portion of the valuable hydrocarbon liquids before they are sent to the flare, increasing the amount of hydrocarbon liquids entering the economic stream, and minimizing the waste and pollution associated with burning these valuable and much-needed products.
Also, burning hydrocarbon liquids generates considerable air pollution. This sort of air pollution was targeted in the Clean Air Act of 1970 as a known carcinogen. The present invention not only returns valuable hydrocarbons to the economic stream, it also generates a “green” benefit by reducing smog and the health hazards associated with it.
The present invention addresses this problem by providing a trailer mounted condensate collection system that is capable of using the pressure from the well to operate the system without the need for outside utilities. The system is a trailer mounted condensate optimization system designed to capture otherwise flared or lost hydrocarbon liquids. The system includes a trailer mounted condenser and a trailer mounted separator. It is specifically designed to be rugged enough for transportation to any well site on what are typically rough lease roads.
The present system treats the gases flowing from the well to condense, separate, and recover those gases that are capable of being condensed to a liquid from those gases that are non-condensable. Once on site, the system is connected to the well's flow line on the inlet end of the system and to the oil storage tank. The system is also connected on its outlet end to a flare, a vent stack or a gas pipeline when a gas pipeline is available.
The system uses pressure from the well to operate a fan that blows ambient air across a heat exchanger where those hydrocarbons from the wellhead that can be condensed will cool sufficiently to condense to a liquid state.
From the heat exchanger, the mixed gaseous and liquid effluent then flows through a separator where the effluent is initially used to heat the separator and then the effluent is introduced into the separator where the liquid portion is separated from the gaseous portion. The separated liquid portion is discharged to an oil storage tank where the liquids that flowed from the well are stored, and the separated gaseous portion is discharged to a flare to be burned or to a gas pipeline when one is available.
As any oil and gas producing area matures, the infrastructure grows to accommodate the need to gather, refine, and process the hydrocarbons to the greatest benefits of the owners. As this infrastructure is put in place the need for wellhead gas liquids condensation systems will shift to areas still outside the influence of infrastructure systems. Wells still remote to new gas gathering pipeline systems and gas plants will still need mobile condensation collection systems like the present invention, at least until the entire field is blanketed by the necessary pipeline networks. In the known shale oil areas of the United States, these plays are so large it may be a century or more before the infrastructure development is truly complete. That assures the present invention a full and fertile future for many decades ahead.
With over 160 drilling rigs currently running in the Baaken within a 50 mile radius of Williston, N. Dak., and with the price of crude oil still rising steadily, the opportunities for the present system continue to grow. And the Baaken is just one basin and one area. The same conditions exist in other shale reserves.
Rigs are completing wells at a rate of about one per month from spud to completion of fracturing. Therefore, in the Baaken alone, nearly 2000 new wells were completed and brought on line in 2012. The extrapolation of this into a nationwide new shale oil and gas well development makes it clear that there is a great need for the present invention.